It is important when constructing modern homes and other buildings that the attic space of the building be adequately ventilated. The failure to provide adequate ventilation can result in a variety of serious problems including, for example, the accumulation of moisture in and around the attic space and problems associated therewith. A variety of attic ventilation techniques and products have been used over the years to provide attic ventilation. These include open-eve vents, attic fans, and convection vents spaced along a roof near its ridge. More recently, so called “shingle-over ridge vents” have become increasingly ubiquitous in homes and commercial buildings. A shingle-over ridge vent is a long usually plastic panel that generally is installed along the ridge of a roof covering an open slot formed therealong. The ridge vent is formed with air passageways and openings that allow hot air within the attic to escape through the ridge slot while the ridge vent covers the open slot preventing rain and debris from entering the attic. Once installed, the ridge vent is covered over with shingles to provide an aesthetically pleasing substantially normal appearance along the roof ridge.
Ridge vents generally are available in two fundamental configurations; namely, relatively short panel-type ridge vents, which are individually positioned and installed end-to-end along a roof ridge, and so-called “rolled” ridge vents, which are long continuous vents that are provided in rolls and are un-rolled along a roof ridge and attached with nails or staples. Each has its advantages and shortcomings. For instance, panel ridge vents can be designed with more elaborate features such as wind baffles outboard of the vent openings that improve air flow by generating low pressure regions just inboard of the wind baffles in the regions of the vent openings. For this and other reasons, panel-type ridge vents in general are highly efficient at providing attic ventilation. However, they are difficult and time consuming to install because each panel must be installed separately in end-to-end relationship with adjacent panels.
Rolled ridge vents, on the other hand, are simple to install relative to panel-type ridge vents because a roofer need only roll the vent out along the ridge, cut it to length, and attach it to the roof. However, since rolled ridge vents must be flexible in order to be rolled, they typically are much less sophisticated in design and configuration than panel-type ridge vents. Sometimes rolled ridge vents are nothing more that long bats of loosely woven fibrous plastic material that presumably allow air flow to flow through their open weave structure. Traditionally, rolled ridge vents have not included the complex air channels, vents, and wind baffles of panel-type ridge vents. As a result, rolled ridge vents, although easy to install, have been shown to be exceedingly inefficient at providing attic ventilation and some are not much better than having no vent at all.
At least one attempt has been made to develop a ridge ventilation system that is rollable into compact rolls for convenient storage and installation yet that includes some of the sophisticated design features and provides the efficient air flow characteristics of panel-type ridge vents. U.S. Pat. No. 6,260,315 discloses such a rollable ridge vent. In this design, a plastic central panel is formed with wind baffles outboard of the panel's edges. The wind baffles are corrugated or, according to the patent, “undulating,” to allow the panel to be rolled-up into a compact roll similar to open weave mat-type rolled ridge vents. When rolled, the corrugated wind baffles flex in an accordion-like manner to allow for the rolling of the vent. The panel also is formed with a somewhat elaborate array of supports on its underside to maintain spacing between the roof decking and the panel such that air flow allegedly is not restricted. While the design of this ridge vent may be a step in the right direction, it nevertheless has its own set of problems and shortcomings. For example, the corrugated or “undulating” configuration of the wind baffles increases substantially the amount of plastic required to mold the panel and thus increases the cost of the product. This is also true for the elaborate support structures on the underside of the panel. More importantly, the support structures and vent design of this product decreases its net-free-area (NFA) and therefore decreases its ventilation efficiency. It also is believed that the corrugated or undulating shape of the side baffles disrupts the laminar flow of wind across the vent, thereby destroying or degrading the formation of a low pressure region (sometimes referred to as the “venturi effect”) just inboard of the wind baffles, which accounts for much of the increased efficiency of panel-type ridge vents. Accordingly, although the product disclosed in the '315 patent purportedly is rollable, it still fails to provide the corresponding high efficiency ventilation of well designed panel-type ridge vent systems.
Another problem with rollable ridge vents, and, indeed, panel-type ridge vents as well, relates to the need to cut the vents near the end of a ridge along which they are being installed. Specifically, when the end of the ridge is reached during installation, the ridge vent must be cut to length so that the end of the vent is spaced properly from the end of the roof ridge. For rolled ridge vents, this means that the installed length of vent must be cut from the remaining roll. For panel-type ridge vents, the last panel, which can be four or five feet long, often is too long and must be cut, again so that the end of the vent is properly spaced from the end of the roof ridge. In either case, the vent must be carefully measured, marked, and cut with a knife or other sharp tool. This process is time consuming, can be frustrating for the installer, and is subject to human error in measurement and cutting.
Cutting the end of a ridge vent also can result in a gap between the roof deck and the vent panel at the end of a length of ridge vent. Such a gap is unacceptable because it provides an entry point for blowing rain, insects, and vermin to enter the attic. Accordingly, special end plugs are sometimes provided and must be installed in the cut end of the ridge vent to plug the gap. This is even more time consuming and frustrating and can even be skipped by an installer, causing leakage and infestation problems. Another problem when cutting some types of ridge vent is the resulting production of scrap pieces of vent. This is particularly true with molded plastic ridge vents because a length of the cut-off portion of the vent must be removed up to the next end wall and discarded.
Accordingly, a need persists for a ridge vent that provides the ease of installation of a traditional rolled ridge vent product and also the highly efficient air-flow and ventilation characteristics of a panel-type ridge vent system. Such a ridge vent should have a high net free area for unhampered flow of air from the attic space, should require a minimum volume of plastic for its fabrication, and should verifiably exhibit ventilation characteristics comparable to those of panel-type ridge vents. A further need exists for a ridge vent incorporating features that eliminate the need to measure and cut the vent at the end of a roof ridge. These features should allow the vent to be separated manually, quickly, and easily without cutting and, once separated, should provide its own end plug or end wall to prevent leakage and infestation at the end. All of this should be accomplished without creating scrap. It is to the provision of a ridge ventilation system that addresses these and other needs that the present invention is primarily directed.